Update build_style for all templates.

- There's no need to set build_style for custom-install (default).
- gnu_{configure,makefile} renamed to gnu-{configure,makefile}.

srcpkgs/curl/template

@@ -3,7 +3,7 @@ pkgname=curl
 version=7.22.0
 homepage="http://curl.haxx.se"
 distfiles="$homepage/download/$pkgname-$version.tar.bz2"
-build_style=gnu_configure
+build_style=gnu-configure
 configure_args="--enable-ldaps --with-gssapi=/usr \
 	--with-ca-bundle=/etc/ssl/certs/ca-certificates.crt"
 short_desc="Client that groks URLs"